Dynamic pressure registration device for internally registered actuators and over pressure protection devices

ABSTRACT

A fluid regulating device includes a regulator valve having an inlet, an outlet, and a valve port disposed between the inlet and the outlet. An actuator is coupled to the regulator valve and includes a valve disc that displaces between a closed position and an open position. The device also includes an overpressure protection device adapted to stop flow from the inlet to the outlet when pressure in a control cavity reaches a predetermined level. The overpressure protection device includes a sensing tube having a first end in fluid communication with the control cavity and a second end in fluid communication with the outlet. The sensing tube has a first portion extending parallel to the flow axis. One or more apertures are disposed in the sensing tube adjacent to the second end, and each of the apertures has a centerline that is perpendicular to the flow axis.

FIELD OF THE INVENTION

The present invention relates to fluid flow regulating devices such asgas regulators and, more particularly, to gas regulators having a systemto prevent unsafe downstream pressure conditions.

BACKGROUND

The pressure at which typical gas distribution systems supply gas mayvary according to the demands placed on the system, the climate, thesource of supply, and/or other factors. However, most end-userfacilities equipped with gas appliances such as furnaces, ovens, etc.,require the gas to be delivered in accordance with a predeterminedpressure, and at or below a maximum capacity of a gas regulator.Therefore, gas regulators are implemented into these distributionsystems to ensure that the delivered gas meets the requirements of theend-user facilities. Conventional gas regulators generally include aclosed-loop control actuator for sensing and controlling the pressure ofthe delivered gas.

In addition to a closed loop control, some conventional gas regulatorsinclude a balanced trim to improve the reaction of the gas regulator tovariations in the downstream pressure. The balanced trim is adapted toreduce the influence of the upstream pressure on the performance of thegas regulator. The upstream pressure is placed in fluid communicationwith a balancing diaphragm to apply a force to the control element ofthe gas regulator in the opposite direction as the force of thedownstream pressure. Accordingly, as the upstream pressure varies, acorresponding force is applied to balance the force created by theupstream pressure as described further below so that the gas regulatoracts in response to the downstream pressure only.

Some conventional gas regulators also include secondary monitoringdevices (overpressure protection devices), such as overpressuremonitoring devices, slam shut devices, token alarms and the like, thatperform a responsive action if a sensed input pressure, such as apressure downstream of the regulator, varies from a predetermined normaloperating pressure range. An overpressure protection device controls thepressure downstream of the regulator in the event that the regulatorfails, thereby allowing the downstream pressure to increase to undesiredlevels. In the event the regulator fails and the downstream pressurerises above a predetermined monitor setpoint pressure, the overpressureprotection device operates to close the valve port of the regulatorvalve and cut off the flow of gas to the downstream components of thegas distribution system. As demand increases and/or the problem with theregulator is resolved and the downstream pressure drops, theoverpressure protection device opens the valve port and thereby allowsgas flow downstream.

Typically, an overpressure protection device, such as an overpressuremonitoring device, responds in the event that the downstream pressure(i.e., pressure in the outlet) exceeds a cutoff pressure that is sensedby a diaphragm. Specifically, a bottom surface of the diaphragm of theoverpressure monitor partially defines a control cavity such thatpressure in the control cavity acts on the diaphragm. In one embodimentof an overpressure monitoring device, a control line extends from thecontrol cavity to a portion of the outlet of the regulator valve, andthe control line is disposed external to a both a housing of theoverpressure monitoring device and portion of the regulator valvedefining the valve outlet. So configured, downstream pressure isaccurately communicated to the control cavity. However, such aconfiguration may be expensive to install and maintain.

Alternatively, overpressure protection devices may include an internalsense tube that extends from the control cavity to the outlet of theregulator valve and that is disposed through internal portions of thehousing of the overpressure protection device and a portion of the bodyof the regulator valve defining the valve outlet. The internal sensetube may have a generally cylindrical shape having a constantcross-section. The internal sense tube may also have an open terminalend that extends into the regulator valve outlet, and the pressure ofthe fluid flowing within the valve at or adjacent to the outlet issensed through the open terminal end of the internal sense tube. Aportion of the internal sense tube that includes the terminal end mayextend obliquely into the outlet or may extend parallel to the generaldirection of fluid flow through the outlet. However, as flow velocitiesand/or flow demand changes, the pressure communicated to the controlcavity by the internal sense tube may correspondingly vary. Typically, apressure lower than the actual control pressure is communicated to thecontrol cavity via the open terminal end of the internal sense tube,thereby artificially driving the valve to induce boost in regulatingpressures. More specifically, as flow passes over the end of theinternal sense tube, a low pressure zone is created at the open terminalend which results in the registered pressure being lower than the actualpressure. As a result, the accuracy of the pressure measurement changesas the flow rate changes, thereby negatively impacting the ability ofthe overpressure protection device to protect the downstream system.

SUMMARY

In accordance with one exemplary aspect of the present invention, afluid regulating device includes a regulator valve having a valve bodydefining an inlet and an outlet. The regulator valve further includes avalve port disposed between the inlet and the outlet. An actuator iscoupled to the regulator valve and the actuator includes a valve disc,the valve disc disposed within the regulator valve and adapted fordisplacement between a closed position sealingly engaging the valve portand an open position disposed away from the valve port. In the openposition, fluid flowing from the inlet to the outlet flows through theoutlet along a flow axis. The fluid regulating device also includes anoverpressure protection device adapted to stop flow from the inlet tothe outlet when pressure in a control cavity reaches a predeterminedlevel. The overpressure protection device includes a sensing tube, andthe sensing tube has a first end in fluid communication with the controlcavity and a second end in fluid communication with the outlet of the ofthe regulator valve such that the control cavity is in fluidcommunication with the outlet of the of the regulator valve. A firstportion of the sensing tube extends along a tube axis that is parallelto the flow axis, and the first portion extends from a first pointdisposed between the first end and the second end and a second pointdisposed at the second end. One or more apertures are disposed in thesensing tube adjacent to the second end, and each of the one moreapertures has a centerline that is perpendicular to the flow axis.

In accordance with a further exemplary aspect of the present invention,a fluid regulating device includes a regulator valve having a valve bodydefining an inlet and an outlet. The regulator valve further includes avalve port disposed between the inlet and the outlet. An actuator iscoupled to the regulator valve and the actuator includes a valve disc,the valve disc disposed within the regulator valve and adapted fordisplacement between a closed position sealingly engaging the valve portand an open position disposed away from the valve port. In the openposition, fluid flowing from the inlet to the outlet flows through theoutlet along a flow axis. The fluid regulating device also includes anoverpressure protection device adapted to stop flow from the inlet tothe outlet when pressure in a control cavity reaches a predeterminedlevel. The overpressure protection device includes a sensing tube, andthe sensing tube has a first end in fluid communication with the controlcavity and a second end in fluid communication with the outlet of the ofthe regulator valve such that the control cavity is in fluidcommunication with the outlet of the of the regulator valve. A firstportion of the sensing tube extends along a tube axis that is parallelto the flow axis, and the first portion extends from a first pointdisposed between the first end and the second end and a second pointdisposed at the second end. The sensing tube includes a first segment ofthe first portion having a first diameter and a second segment of thefirst portion having a second diameter, wherein the first diameter islarger than the second diameter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side cross-sectional view of an embodiment of a fluidregulating device in an open position, the fluid regulating deviceincluding an overpressure protection device;

FIG. 2 is a partial side cross-sectional view of the valve disc andsensing tube of the fluid regulating device of FIG. 1, the fluidregulating device in a closed position;

FIG. 3 is a partial side cross-sectional view of an embodiment of thesensing tube illustrated in FIGS. 1 and 3;

FIG. 4 is a partial side cross-sectional view of a further embodiment ofthe sensing tube;

FIG. 5 is a partial side cross-sectional view of an additionalembodiment of the sensing tube;

FIG. 6 is a partial side cross-sectional view of a further embodiment ofthe sensing tube;

FIG. 7 is a partial side cross-sectional view of a further embodiment ofthe sensing tube; and

FIG. 8 is a partial side cross-sectional view of a sensing tube thatextends from the outlet of the regulator valve to the control chamber ofthe actuator.

DETAILED DESCRIPTION

FIGS. 1 and 2 illustrate a fluid regulating device 10 including aregulator valve 12 having a valve body 13 defining an inlet 14 and anoutlet 16. The regulator valve 10 further includes a valve port 18disposed between the inlet 14 and the outlet 16. An actuator 20 iscoupled to the regulator valve 12 and the actuator 20 includes a valvedisc 22, the valve disc disposed within the regulator valve 12 andadapted for displacement between a closed position sealingly engagingthe valve port 18 and an open position disposed away from the valve port18. In the open position, fluid flowing from the inlet 14 to the outletflows through the outlet along a flow axis 24. The fluid regulatingdevice 10 also includes an overpressure protection device 25 (such as anoverpressure monitor 26) adapted to stop flow from the inlet 14 to theoutlet 16 when pressure in a control cavity 27 rises or falls to apredetermined level.

As illustrated in FIG. 2, the overpressure protection device 25 includesa sensing tube 28, and the sensing tube 28 has a first end 29 in fluidcommunication with the control cavity 27 and a second end 30 in fluidcommunication with the outlet 16 of the of the regulator valve 12 suchthat the control cavity 27 is in fluid communication with the outlet 16of the of the regulator valve 12. A first portion 31 of the sensing tube28 extends along a tube axis 37 that is parallel to the flow axis 24,and the first portion 31 extends from a first point 32 disposed betweenthe first end 29 and the second end 30 and a second point 33 disposed atthe second end 30. One or more apertures 34 are disposed in the sensingtube 28 adjacent to the second end 30, and each of the one moreapertures 34 has a centerline 35 that is perpendicular to the flow axis24. So configured, pressure normal to the flow tube is communicated tothe control cavity 27, thereby eliminating the low pressure zone thatresults in the inaccurate registration of pressure. As a result, thepressure registered by the overpressure protection device 25 is accurateand is not affected by variations in flow velocities and flow demand.

Turning to the fluid regulating device 10 in more detail, the fluidregulating device 10 includes the actuator 20 and the regulator valve12, as illustrated in FIGS. 1 and 2. The regulator valve 12 includes theinlet 14 for receiving gas from a gas distribution system, for example,and the outlet 16 for delivering gas to a facility having one or moreappliances, for example. The actuator 20 is coupled to the regulatorvalve 12 and includes a control assembly 36 having a control element,such as a valve disc 22. During a first or normal operational mode, thecontrol assembly 36 senses the pressure at the outlet 16 of theregulator valve 12 (i.e., the outlet pressure) and controls a positionof the valve disc 22 such that the outlet pressure approximately equalsa predetermined setpoint or control pressure.

With reference to FIGS. 1 and 2, the regulator valve 12 defines a throat38 and a valve mouth 40. The throat 38 is disposed between the inlet 14and the outlet 16, and has the valve port 18 disposed therein. Fluidmust travel through the valve port 18 to travel between the inlet 14 andthe outlet 16 of the regulator valve 12. The valve port 18 may beremovable from the regulator valve 12 such that it may be replaced witha different valve port having a bore of a different diameter orconfiguration to tailor operational and flow characteristics of theregulator valve 12 to a specific application. In the disclosedembodiment, the valve mouth 40 defines an opening disposed along an axisthat is generally parallel to a horizontal (i.e., extending along orparallel to the X axis of the reference coordinate system provided inFIG. 1) longitudinal axis 149 and that may be perpendicular orsubstantially perpendicular to the vertical (i.e., extending along orparallel to the Y axis of the reference coordinate system provided inFIG. 1) flow axis 24 aligned or substantially aligned with the generaldirection of fluid flow through the inlet 14 and outlet 16 of theregulator valve 12.

Referring to FIG. 1, the actuator 20 includes a housing 42 and thecontrol assembly 36, as discussed above. The housing 42 includes anupper housing component 42 a and a lower housing component 42 b securedtogether with a plurality of fasteners, for example. The lower housingcomponent 42 b defines a control cavity 44 and an actuator mouth 46. Theactuator mouth 46 is connected to the valve mouth 40 of the regulatorvalve 12 to provide fluid communication between the actuator 20 and theregulator valve 12. The upper housing component 42 a defines a reliefcavity 48 and a tower portion 50 for accommodating a portion of thecontrol assembly 36, as will be described.

The control assembly 36 includes a diaphragm subassembly 52, a disc andbalancing subassembly 54, and a release valve 56. The diaphragmsubassembly 52 includes a diaphragm 58, a piston 60, a control spring62, a relief spring 64, a combination spring seat 68, a relief springseat 72, a control spring seat 76, and a piston guide 80. Moreparticularly, the diaphragm 58 includes a disc-shaped diaphragm definingan opening through a central portion thereof. The diaphragm 58 isconstructed of a flexible, substantially air-tight, material and itsperiphery is sealingly secured between the upper and lower housingcomponents 42 a, 42 b of the housing 42. The diaphragm 58 thereforeseparates the relief cavity 48 from the control cavity 44.

The combination spring seat 68 is disposed on top of the diaphragm 58and defines an opening disposed concentric with the opening in thediaphragm 58. As depicted in FIG. 1, the combination spring seat 68supports the control spring 62 and the relief spring 64.

The piston 60 of the disclosed embodiment includes a generally elongatedrod-shaped member having a sealing cup portion 84, a yoke 88, a threadedportion 92, and a guide portion 96. The sealing cup portion 84 isconcaved and generally disc-shaped and extends circumferentially about amid-portion of the piston 60, and is located just below the diaphragm58. The yoke 88 includes a cavity adapted to accommodate a coupler 100that connects to a portion of the disc and balancing subassembly 54 toenable attachment between the diaphragm subassembly 52 and the disc andbalancing subassembly 54, as will be described.

The guide portion 96 and the threaded portion 92 of the piston 60 aredisposed through the openings in the diaphragm 58 and the combinationspring seat 68, respectively. The guide portion 96 of the piston 60 isslidably disposed in a cavity in the piston guide 80, which maintainsthe axial alignment of the piston 60 relative to the remainder of thecontrol assembly 36. The relief spring 64, the relief spring seat 72,and a nut 104 are disposed on the threaded portion 92 of the piston 60.The nut 104 retains the relief spring 64 between the combination springseat 68 and the relief spring seat 72. The control spring 62 is disposedon top of the combination spring seat 68, as mentioned, and within thetower portion 50 of the upper housing component 42 a. The control springseat 74 is threaded into the tower portion 50 and compresses the controlspring 62 against the combination spring seat 68. In the disclosedembodiment, the control spring 62 and the relief spring 64 includecompression coil springs. Accordingly, the control spring 62 is groundedagainst the upper housing component 42 a and applies a downward force tothe combination spring seat 68 and the diaphragm 58. The relief spring64 is grounded against the combination spring seat 68 and applies anupward force to the relief spring seat 72, which in turn is applied tothe piston 60. In the disclosed embodiment, the force generated by thecontrol spring 62 is adjustable by adjusting the position of the controlspring seat 74 in the tower portion 50, and therefore the controlpressure of the regulator 10 is also adjustable.

The control spring 62 acts against the pressure in the control cavity44, which is sensed by the diaphragm 58. As stated, this pressure is thesame pressure as that which exists at the outlet 16 of the regulatorvalve 12. Accordingly, the force applied by the control spring 62 setsthe outlet pressure to a desired setpoint or control pressure for theregulator 10. The diaphragm subassembly 52 is operably coupled to thevalve disc 22 and balancing subassembly 54, as mentioned above, via theyoke 88 of the piston 60 and the coupler 100, and by a control arm 108.

The disc and balancing subassembly 54 includes an actuator stem 112 thatis engaged by the control arm 108 to move the valve disc 22 between theopen and closed positions as the diaphragm 58 flexes due to variationsin the downstream pressure. Specifically, the actuator stem 112 is agenerally linear rod having an end surface engaged by the control arm108. The control arm 108 is a slightly curved rod and includes a fulcrumend 108 a and a free end 108 b. The fulcrum end 108 a is pivotallycoupled to the lower housing component 130 b and includes a finger 113having a rounded end and engaging the end surface of the actuator stem112. The free end 108 b is received between a top portion and a pin ofthe coupler 100 that is attached to the yoke 88 of the piston 60. Thus,the coupler 100 and the control arm 108 operably connect the disc andbalancing subassembly 54 to the diaphragm subassembly 52.

As illustrated in FIG. 2, the valve disc 22 of the disc and balancingsubassembly 54 is operatively connected to the actuator stem 112, andincludes a sealing surface 150 that engages the outlet of the valve port18 to cut off the fluid flow through the regulator valve 12. The sealingsurface 150 may be a portion of the valve disc 22 itself, or may be aportion of a sealing insert secured within a cavity formed in the valvedisc 22. The sealing surface 150 may include any suitable material orcombination of materials, such as a resilient, compressible material.The sealing

The valve disc 22 may be directly or indirectly connected to theactuator stem 112 by a balanced port stem 116 (that is secured to thevalve disc 22) and a balancing spring seat 120, and the combinedelements are supported for linear movement by a stem guide 124, aretainer plate 128, a balancing diaphragm retainer 132 and a balancingport housing 136. The stem guide 124 is configured to fit within theactuator mouth 46, and includes a generally cylindrical inner portionthat slidably retains the actuator stem 112. The stem guide 124 furtherincludes channels 140 therethrough forming a portion of the path placingthe outlet 16 in fluid communication with control cavity 44 as discussedfurther below.

Referring to FIG. 2, the stem guide 124 engages the retainer plate 128,which is disposed between the stem guide 124 and balanced port housing136, to hold the retainer plate 128 and balanced port housing 136 inplace within the valve mouth 126. The retainer plate 128 is generallycircular and includes a central opening through which the balanced portstem 116 passes. The balanced port housing 136 is generally cylindricaland hollow, extends toward the valve port 18, and has an inner diametersized to slidably receive the valve disc 22. The diaphragm retainer 132is disposed within the balanced port housing 136 and the opening of theretainer plate 128, and is held in place between a surface of theretainer plate 128 and an inner shoulder of the balanced port housing136. A disc-shaped balancing diaphragm 144 having a central opening isprovided within the balanced port housing 136. The balancing diaphragm144 is constructed of a flexible, substantially air-tight, material andits periphery is secured between the diaphragm retainer 132 and thebalanced port housing 136. The inner edge at the central opening of thebalancing diaphragm 144 is sealingly secured between the valve disc 22and the balanced port stem 116. So configured, a first cavity 152 isformed between a portion of the valve disc 22, the diaphragm retainer132, and a surface of the balancing diaphragm 144.

The valve disc 22, the balanced port stem 116 secured to the valve disc22, and the actuator stem 112 may be biased toward the open position ofthe regulator valve 12 by a balancing spring 148 disposed between thebalancing spring seat 120 and a seating surface of the diaphragmretainer 132. More specifically, the seating surface of the diaphragmretainer 132 may be adapted to seat a first end of the balancing spring148 and a second end of the balancing spring 148 may be adapted toengage a portion of the balancing spring seat 120, as illustrated inFIG. 2. The balancing spring 148 may be any suitable resilient member,such as a coil spring that is coaxially aligned with the longitudinalaxis 24. Because the seating surface of the diaphragm retainer 132 isstationary, the second end of the balancing spring 148 biases thebalancing spring seat 120 into engagement with the actuator stem 112.The balancing spring 148 may be pre-stressed to provide a suitablebiasing force regardless of the position of the actuator stem 112.Moreover, the balancing spring 148 may be chosen from a plurality ofbalancing springs that each have a unique spring characteristics (e.g.,spring force) to tune the disc and balancing subassembly 54 to achievedesired flow conditions.

As illustrated in FIG. 2, the valve disc 22 of the disc and balancingsubassembly 54 includes the sealing surface 150 disposed at a first endof the valve disc 22. The valve disc 22 may further include one or moredisc passages 151 that may longitudinally extend through the valve disc22 from the first end to a longitudinally opposite second end such thatthe first cavity 152 is in fluid communication with the area adjacent tothe outlet 125 of the valve port 18. The one or more disc passages 151may be formed as a combination of one or more cylindrical passagewaysand one or more planar passageways that extend through the valve disc22. In addition, one or more of the disc passages 151 may at leastpartially include elongated longitudinal passageways having any suitablecross-sectional shape (such as round, oval, or polygonal, for example).

With the valve disc 22 in the open position, fluid flows through the oneor more disc passages 155 from the outlet 125 of the valve port 18 intothe first cavity 152 and into contact with the balancing diaphragm 144.As such, the one or more disc passages 151 are configured to place thesurface of the balancing diaphragm 144 opposite the valve port 18 influid communication with the upstream pressure bearing on the valve disc22. Accordingly, the balancing diaphragm 144 provides a force on thevalve disc 22 in the direction of the valve port 18 to compensate forthe force applied to the valve disc 22 due to the upstream pressure ofthe fluid passing through the valve port 18. The components of the discand balancing subassembly 54 are configured so that the force applied bythe balancing diaphragm 144 is approximately opposite and equal to theforce of the upstream pressure on the valve disc 22 to eliminate anyinfluence of the upstream pressure on the diaphragm subassembly 52 andthereby allowing for more accurate control of the downstream pressure bythe fluid regulating device 10.

As illustrated in FIG. 1, the fluid regulating device 10 may alsoinclude a secondary device in the form of an overpressure protectiondevice 25 that operates to cut off the fluid flow through the regulatorvalve 12 in an overpressure situation until the downstream pressure isreduced after a failure of the actuator 20. As would be understood byone having ordinary skill in the art, the overpressure protection device25 may be an overpressure monitoring device, a slam shut device, a tokenalarm, or any similar device known in the art that operates to cut offthe fluid flow through a valve 12 in an overpressure situation until thedownstream pressure is reduced after a failure of the actuator 20

For example, as illustrated in FIG. 2, the overpressure protectiondevice 25 may be an overpressure monitor 26 that has a configurationsimilar to the actuator 20, and the overpressure monitor 26 alsooperates in a similar manner as the actuator 20. Because theoverpressure monitor 26 only responds in the event that the downstreampressure (i.e., pressure in the outlet 16) exceeds a cutoff pressureestablished by a diaphragm 248 and a control spring 252, a monitordiaphragm subassembly 242 and a disc and balancing subassembly 244 areconfigured accordingly. A bottom surface of the diaphragm 248 of theoverpressure monitor 26 partially defines the control cavity 27 suchthat pressure in the control cavity 27 acts on the diaphragm 248, andthe control cavity 27 is in fluid communication with the outlet 16 ofthe regulator valve 12 via the sensing tube 28 to allow the downstreampressure to act on the diaphragm 248.

As illustrated in FIGS. 1 and 2, the sensing tube 28 (i.e., a piezometertube) of the overpressure monitor 26 may be formed as a cylindrical tubeor may be partially formed of a cylindrical tube. However, the sensingtube 28 may have any suitable cross-sectional shape or combination ofshapes, such as that of an oval or polygon, for example. The sensingtube 28 may be formed as a single, unitary part, or may include two ormore sub-component parts that are secured together to form the sensingtube 28. The sensing tube 28 may have any suitable thickness orthicknesses, and the sensing tube 28 may be made of any suitablematerial or combination of materials (e.g., steel, brass, aluminum,etc.).

Still referring to FIGS. 1 and 2, the first end 29 of the sensing tube28 is in fluid communication with the control cavity 27 and the secondend 30 of the sensing tube 28 is in fluid communication with the outlet16 of the of the regulator valve 12. So configured, the control cavity27 is in fluid communication with the outlet 16 of the of the regulatorvalve 12. The sensing tube 28 may have a first portion 31 that extendsalong a tube axis 37 that is parallel to or substantially parallel tothe vertical flow axis 24. The first portion 31 extends from a firstpoint 32 (disposed between the first end 29 of the sensing tube 28 andthe second end 30 of the sensing tube 28) and a second point 33(disposed at the second end 30 of the sensing tube), and the first point32 is downstream of the second end 30. The first portion 31 may bedisposed entirely within the outlet 16 of the regulator valve 12 or thefirst portion 31 may at least partially extend into a segment of pipesecured to the outlet 16.

The sensing tube 28 may have a second portion 153 that extends from thefirst end 29 of the sensing tube 28 to the first point 32 of the firstportion 31 of the sensing tube 28. The second portion 153 may have anysuitable shape or combination of shapes that allows the first end 29 ofthe sensing tube 28 to be in fluid communication with the control cavity27 and that allows the second portion 153 to extend to the first point32 of the first portion 31 of the sensing tube 28. For example, thesecond portion 153 may have a curved or substantially curved shape whenviewed in cross section. Alternatively, one or more linear segments orone or more rounded or curved segments may cooperate to form the secondportion 153. The second portion 153 may at least partially extendthrough the housing 230 of the overpressure monitor 26 at or adjacent tothe interface between the overpressure monitor 26 and the actuator valve12. The second portion 153 may also at least partially extend through aportion of the valve body 13 of the actuator valve 12 that defines theoutlet 16. The second portion 153 may also be defined as a channel (or atube disposed within a channel) extending through the housing 230 of theoverpressure monitor 26 and/or the valve body 13 of the actuator valve12 that defines the outlet 16 (or that is adjacent to the outlet 16),and the first portion 31 may be secured to a portion of the valve body13 of the actuator valve 12 that defines the outlet 16 (or that isadjacent to the outlet 16).

In the embodiment of the sensing tube 28 illustrated in FIGS. 2 and 3,one or more apertures 34 are disposed in the sensing tube 28 adjacent tothe second end 30, and each of the one more apertures 34 has acenterline 35 that is perpendicular to the tube axis 37 and the flowaxis 24. That is, each of the one or more apertures 34 extends from anouter surface 154 of the sensing tube 28 to an inner surface 155 of thesensing tube 28. So configured, each of the one or more apertures 34 isformed on or through a surface (i.e., the outer surface 154) thatextends along or parallel to the flow axis 24 (or the tube axis 37).Each of the outer surface 154 and the inner surface 155 may extend alongthe tube axis 37 and each may be cylindrical, oval, or polygonal, forexample. Any number of apertures 34 may be formed through the sensingtube 28. For example, at least three apertures 34 may be disposed in thesensing tube 28, and the at least three apertures 34 may be spaced atequal radial intervals around a circumference of the sensing tube 28. Acenterline 35 of each of the at least three apertures 34 may be disposedin a reference plane that is normal to the tube axis 37 and/or the flowaxis 24. In one embodiment, four apertures 34 may be formed in thesensing tube 28. The one or more apertures 34 may have any suitableshape, such as that of a circle or an oval (when viewed along thecenterline 35) and may have any suitable size that allows for fluid toflow through the aperture 34 and into the control cavity 27.

The sensing tube 28 may include a vertical or substantially vertical endwall 156 disposed at or adjacent to the second end 30 of the sensingtube 28. The end wall 156 may be solid (i.e., non-porous) and may beadapted to prevent fluid flow into (and out of) the second end 30 of thesensing tube 28 along the tube axis 37 (and the flow axis 24). Soconfigured, fluid flowing in the outlet may only enter the sensing tube28 through the one or more apertures 34. Thus, fluid pressure may not besensed longitudinally (i.e., along the tube axis 37) through the secondend 30 of the sensing tube 28—rather, fluid pressure is sensed throughthe one or more apertures 34. By sensing pressure through apertures 34extending normal to the tube axis 37, a low pressure zone adjacent tothe apertures 34 is avoided, resulting in an accurate registration ofpressure by the overpressure monitor 26.

In the embodiment of the sensing tube 28 illustrated in FIG. 5, one ormore projection members 157 may extend from the outer surface 154 of thesensing tube 28 adjacent to the second end 30. Each of the projectionmembers 157 may extend normal or substantially normal to the tube axis37 (and the flow axis 24). In addition, each of the projection members34 may be disposed between the one or more apertures 34 and the secondpoint 33 at the second end 30 of the sensing tube 28. So configured, aprojection member 157 may be adjacent to a corresponding aperture 34such that the number of projection members 157 equals the number ofapertures 34. The projection members 157 may have any suitable shapeadapted to create turbulence in the flow of fluid at or adjacent to acorresponding aperture 34. This turbulence improves the accuracy of thesensed pressure within the outlet 16 that is communicated to theoverpressure monitor 26. As illustrated in FIG. 5, the projectionmembers 157 may be elongated and may have a circular, polygonal, or ovalcross-sectional shape.

In the embodiment of the sensing tube 28 illustrated in FIG. 4, at leasta portion of the first portion 31 of the sensing tube 28 includes a baseportion 158 having an outer surface 159, and the outer surface 159 maybe cylindrical. The first portion 31 may also include a cap 160 that maybe disposed at a terminal end of the base portion 158. The cap may havean outer surface 161 and an inner surface 162, and each of the outer 161and inner surfaces 162 may be cylindrical. The inner surface 162 of thecap 160 may have a diameter that is slightly larger than the diameter ofthe outer surface 159 of the base portion 158 such that the terminal endof the base portion 160 is received into an interior of the cap 160(i.e., such that a portion of the outer surface of the 159 of the baseportion 158 is adjacent to or in contact with a portion of the innersurface 162 of the cap 160. The cap 160 may be secured to the baseportion 158 in any manner known in the art, such as welding, adhesives,or an interference fit, for example.

The cap 160 of the sensing tube 28 may include a vertical orsubstantially vertical end wall 163 disposed at or adjacent to thesecond end 30 of the sensing tube 28 adjacent to an end portion of thecap 160. The end wall 163 may be solid (i.e., non-porous) and may beadapted to prevent fluid flow into (and out of) the second end 30 of thesensing tube 28 along the tube axis 37 (and the flow axis 24). Anynumber of apertures 34 may be formed through the cap 28, and theapertures 134 may be identical or substantially identical to theapertures 134 previously described. For example, at least threeapertures 34 may be disposed in the cap 160, and the at least threeapertures 34 may be spaced at equal radial intervals around acircumference of the cap 160. In one embodiment, six apertures 34 may beformed in the sensing tube 28. A vertical surface 164 may extend betweenthe outer surface 161 of the cap 160 and the outer surface 159 of thebase portion 158, and the vertical surface 164 may be disposed betweenthe one or more apertures 134 and the first point 32 of the firstportion 31 of the sensing tube 28. The vertical surface 164 may benormal or substantially normal to the tube axis 37 or may be conical orfrustoconical. The vertical surface 164 may be a projection member 157adapted to create turbulence in the flow of fluid at or adjacent to acorresponding aperture 34. This turbulence improves the accuracy of thesensed pressure within the outlet 16 that is communicated to theoverpressure monitor 26.

In the embodiment of the sensing tube 28 illustrated in FIG. 6, thesensing tube 128 may be identical or substantially identical to thepreviously-described embodiments, but the sensing tube 28 may notinclude one or more apertures 34 extending normal to the tube axis 37.Instead, fluid can flow into an interior portion of the sensing tube 28through an open second end 30, the open second end including a mouthportion 165. The mouth portion 165 may include an annular mouth surface166 that that extends around the perimeter of the mouth portion betweenthe outer surface 154 and the inner surface 155 of the first portion 31.The mouth surface 166 may be planar or may be at least partiallycontoured or rounded. The mouth surface 166 may be coplanar orsubstantially coplanar with a reference plane, and the reference planemay intersect the tube axis 37 to form an oblique angle (i.e., an angleless than 90 degrees). That is, when viewed normal to the tube axis 37,the reference plane may appear as a linear reference axis 167 that formsan oblique angle A with the tube axis 37. Specifically, the angle Abetween the reference axis 167 and the tube axis 37 may be between 10degrees and 80 degrees, and preferably between 40 degrees and 55degrees. So configured, the mouth portion 165 includes an acute portion168 that is defined by the reference axis 167 and the outer surface 154of the sensing tube 28 when viewed normal to the tube axis 37. Whenviewed normal to the tube axis 37, a tip of the acute portion 168projects longitudinally forward of the sensing tube 28, and the acuteportion 168 may be disposed on a lateral side of the sensing tube 28closest to a centerline 180 of the outlet 16 (when viewed normal to thetube axis 37). So configured, a low pressure vortex at the second end 30caused by fluid flow is prevented, thereby improving the accuracy of thesensed pressure within the outlet 16 that is communicated to theoverpressure monitor 26.

In the embodiment of the sensing tube 28 illustrated in FIG. 7, thesensing tube 128 may be similar to the previously-described embodiments,but the sensing tube 28 does not have one or more apertures 134.Instead, fluid can flow into an interior portion of the sensing tube 28through an open second end 30. In the embodiment of FIG. 7, a firstsegment 169 of the first portion 31 may have a cylindrical shape havinga first inner diameter D1 and a second segment 170 of the first portion31 may have a cylindrical shape having a second diameter D2 that isdifferent from the first diameter D1. For example, the first diameter D1may be larger than the second diameter D2. More specifically, the firstdiameter D1 may be between two and four times larger than the seconddiameter D2. The second segment 170 may be adjacent to the second end 30of the sensing tube 28. The sensing tube 28 may also include atransition segment 171 disposed between the first segment 169 and thesecond segment 170. The transition segment 171 may have a variable innerdiameter that gradually reduces from the first diameter D1 to the seconddiameter D2 along the length of the transition segment 171. The firstand second segments 169, 170 may have any suitable length. For example,a longitudinal length of the first segment 169 may be at least fivetimes longer than a longitudinal length of the second segment 170. Inaddition, a longitudinal length of the second segment 170 may be betweentwo and six times longer than the second diameter D2 of the secondsegment 170. So configured, a low pressure vortex at the second end 30caused by fluid flow is prevented, thereby improving the accuracy of thesensed pressure within the outlet 16 that is communicated to theoverpressure monitor 26.

Referring again to FIG. 1, the overpressure monitor 26 further includesa balancing spring 214 disposed between a spring seat 286 and adiaphragm retainer 292 biases a valve disc 222 to the normal openposition. A coupler 272 and a control arm 276 are configured so that thecoupler 272 only drives the control arm 276 in the direction to move thevalve disc 222 toward the closed position and into engagement with theupstream side of the valve port 18 to cut off the fluid flow through theregulator valve 12. A pin 272 a of the coupler 272 engages the free end276 b of the control arm 276 to rotate the control arm 276 when thediaphragm 248 and a piston 250 move upward due to a downstream pressureexceeding the cutoff pressure. Conversely, a top portion 272 a of thecoupler 272 is disposed remotely from the control arm 276 so thedownward movement of the diaphragm 248 and piston 250 caused bydecreases in the downstream pressure do not cause movement of thecontrol arm 276. Of course, alternate configurations of overpressuremonitors are known to those skilled in the art, including monitorsconfigured to close when the downstream pressure drops below a lowpressure cutoff, and are contemplated by the inventors as having use ingas regulators in accordance with the present disclosure.

When an operating demand is placed on the gas distribution system, e.g.,a user begins operating an appliance such as a furnace, a stove, etc.,the appliance draws gas from the outlet 16 and correspondingly thecontrol cavity 44 of the actuator 20 and the control cavity 27 of theoverpressure monitor 26, thereby reducing the pressure that is sensed bythe diaphragms 58, 248. As the pressure sensed by the diaphragm 58decreases, a force imbalance occurs between a control spring force andan outlet pressure force on the diaphragm 58 such that the controlspring 62 expands and displaces the diaphragm 58 and piston 60 downwardrelative to the housing 42. This causes the control arm 108 to pivot inthe clockwise direction, which in turn rotates the finger 113 relativeto the surface of the actuator stem 112. This allows the actuator stem112 and the valve disc 22 to move away from the outlet 125 of the valveport 18 due to the force of the balancing spring 148 to open theregulator valve 12. At the same time, the pressure decrease may alsocause a force imbalance to occur between a control spring force and anoutlet pressure force on the diaphragm 248 such that the control spring252 expands and displaces the diaphragm 248 and piston 250 downwardrelative to the housing 230. However, because the upper portion of thecoupler 272 is disposed remotely from the control arm 276, theoverpressure monitor 26 does not similarly respond to the drop inpressure with movement of the valve disc 222.

When the demand is removed from the gas distribution system, such aswhen the user shuts off the appliance, the regulator 10 initiallyresponds by decreasing the fluid flow through the regulator valve 12. Asgas continues to flow through the valve port 18 and to the downstreamportion of the system, the pressure increases at the outlet 16 and,correspondingly, in the control cavity 44 of the actuator 20 and thecontrol cavity 27 of the overpressure monitor 26. As the pressure sensedby the diaphragm 58 increases and overcomes the control spring force,the diaphragm 58 and piston 60 are forced upward relative to the housing42. The upward movement causes the control arm 108 to pivot in thecounterclockwise direction, which in turn drives the actuator stem 112and the valve disc 22 toward the valve port 18 to reduce the fluid flowthrough the regulator valve 12. Under normal operating conditions, theoutlet pressure will drop to approximately the actuator setpointpressure and remain there until the downstream demand changes in amanner that causes a response from by the actuator 20.

The monitor cutoff pressure is greater than the actuator setpointpressure, and the overpressure monitor 26 does not typically respond topressure variations within the normal operating range of the fluidregulating device 10. In the event of a failure of the actuator 20 suchas, for example, the rupturing of the diaphragm 58, the valve disc 22may remain open despite increases in the downstream pressure beyond theactuator setpoint pressure. Eventually, the pressure at the second end30 of the sensing tube 28 reaches the cutoff pressure of theoverpressure monitor 26. The downstream pressure communicated to thecontrol cavity 27 by the sensing tube 28 causes a force imbalance tooccur between the control spring force and the outlet pressure force onthe diaphragm 248 such that the control spring 252 contracts anddisplaces the diaphragm 248 and piston 250 upward relative to thehousing 230. When the piston 250 moves, the pin 272 a of the coupler 272rotates the control arm 276 to drive the actuator 278 and move the valvedisc 222 into engagement with the valve port 18 to shut off the fluidflow through the regulator valve 12. The overpressure monitor 26 willcontinue to stop the fluid flow as long as the pressure at the secondend 30 of the sensing tube 28 remains above the monitor cutoff pressure.

As illustrated in FIG. 8, an embodiment of the fluid regulating device10 may have a sensing tube 28 adapted to sense pressure in a primaryregulator (i.e., the actuator 20) instead of sensing pressure in anoverpressure protection device 25. In this embodiment, the fluidregulating device 10 may or may not have an overpressure protectiondevice 25, and an additional sensing tube 28 may be employed to sensepressure in the overpressure protection device 25 as previouslydescribed. The sensing tube 28 employed with the actuator 20 may beidentical or substantially identical to the embodiments previouslydescribed. However, the first end 29 of the sensing tube 28 may be influid communication with the control cavity 44 of the actuator 20 andthe second end 30 of the sensing tube 28 may be in fluid communicationwith the outlet 16 of the of the regulator valve 12 (or with the inlet14 of the regulator valve 12). So configured, the control cavity 44 isin fluid communication with the outlet 16 (or inlet 14) of the of theregulator valve 12. The sensing tube 28 may have a first portion 31 thatextends along a tube axis 37 that is parallel to or substantiallyparallel to the vertical flow axis 24. The first portion 31 extends froma first point 32 (disposed between the first end 29 of the sensing tube28 and the second end 30 of the sensing tube 28) and a second point 33(disposed at the second end 30 of the sensing tube), and the first point32 is downstream of the second end 30. However, the orientation of thefirst portion 31 may be reversed such that the first point 32 isupstream of the second end 30. The first portion 31 may be disposedentirely within the outlet 16 of the regulator valve 12 or the firstportion 31 may at least partially extend into a segment of pipe securedto the outlet 16.

Still referring to FIG. 8, the sensing tube 28 may have a second portion153 that extends from the first end 29 of the sensing tube 28 to thefirst point 32 of the first portion 31 of the sensing tube 28. Thesecond portion 153 may have any suitable shape or combination of shapesthat allows the first end 29 of the sensing tube 28 to be in fluidcommunication with the control cavity 44 and that allows the secondportion 153 to extend to the first point 32 of the first portion 31 ofthe sensing tube 28. For example, the second portion 153 may have acurved or substantially curved shape when viewed in cross section.Alternatively, one or more linear segments or one or more rounded orcurved segments may cooperate to form the second portion 153. The secondportion 153 may at least partially extend through the actuator mouth 46of the actuator 20 at or adjacent to the interface between the actuator20 and the actuator valve 12. The second portion 153 may also at leastpartially extend through a portion of the valve body 13 of the actuatorvalve 12 that defines the outlet 16 (or the inlet 14). The secondportion 153 may also be defined as a channel (or a tube disposed withina channel) extending through the actuator mouth 46 of the actuator 20and/or the valve body 13 of the actuator valve 12 that defines theoutlet 16 or inlet 14 (or that is adjacent to the outlet 16 or inlet14), and the first portion 31 may be secured to a portion of the valvebody 13 of the actuator valve 12 that defines the outlet 16 or inlet 14(or that is adjacent to the outlet 16 or inlet 14). In the mannerpreviously described, the embodiments of the sensing tube 28 provide anaccurate registration of pressure by the actuator 20.

While certain representative embodiments and details have been shown forpurposes of illustrating the invention, it will be apparent to thoseskilled in the art that various changes in the methods and apparatusdisclosed herein may be made without departing from the scope of theinvention.

What is claimed:
 1. A fluid regulating device, comprising: a regulatorvalve having a valve body defining an inlet and an outlet, the regulatorvalve further including a valve port disposed between the inlet and theoutlet; an actuator coupled to the regulator valve and comprising avalve disc, the valve disc disposed within the regulator valve andadapted for displacement between a closed position sealingly engagingthe valve port and an open position disposed away from the valve port,wherein in the open position, fluid flowing from the inlet to the outletflows through the outlet along a flow axis; an overpressure protectiondevice adapted to stop flow from the inlet to the outlet when pressurein a control cavity reaches a predetermined level, the overpressureprotection device having a sensing tube, the sensing tube having a firstend in fluid communication with the control cavity and a second end influid communication with the outlet of the of the regulator valve suchthat the control cavity is in fluid communication with the outlet of theof the regulator valve, wherein a first portion of the sensing tubeextends along a tube axis that is parallel to the flow axis and whereinthe first portion extends from a first point disposed between the firstend and the second end and a second point disposed at the second end,and wherein one or more apertures are disposed in the sensing tubeadjacent to the second end, each of the one or more apertures having acenterline that is normal to the tube axis.
 2. The fluid regulatingdevice of claim 1, wherein an end wall is disposed adjacent to thesecond end of the sensing tube, the end wall being adapted to preventfluid flow into or out of the second end of the sensing tube along thetube axis.
 3. The fluid regulating device of claim 2, wherein one ormore projection members extend from an outer surface of the sensing tubeadjacent to the second end of the sensing tube.
 4. The fluid regulatingdevice of claim 3, wherein the one or more projection members isdisposed between the one or more apertures and the second point at thesecond end of the sensing tube.
 5. The fluid regulating device of claim1, wherein the sensing tube includes a cap secured to a base portionadjacent to the second end of the sensing tube, and wherein the one ormore apertures are disposed in the cap.
 6. The fluid regulating deviceof claim 5, wherein an end wall vertically extends between an outersurface of the cap and an outer surface of the base portion.
 7. Thefluid regulating device of claim 5, wherein the end wall is disposedbetween the one or more apertures and the second end of the sensingtube.
 8. The fluid regulating device of claim 1, wherein at least threeapertures are disposed in the sensing tube.
 9. The fluid regulatingdevice of claim 8, wherein the at least three apertures are spaced atequal radial intervals around a circumference of the sensing tube. 10.The fluid regulating device of claim 8, wherein a centerline of each ofthe at least three apertures are disposed in a reference plane that isnormal to the tube axis.
 11. The fluid regulating device of claim 1,wherein the overpressure protection device is an overpressure monitor.12. A fluid regulating device, comprising: a regulator valve having avalve body defining an inlet and an outlet, the regulator valve furtherincluding a valve port disposed between the inlet and the outlet; anactuator coupled to the regulator valve and comprising a valve disc, thevalve disc disposed within the regulator valve and adapted fordisplacement between a closed position sealingly engaging the valve portand an open position disposed away from the valve port, wherein in theopen position, fluid flowing from the inlet to the outlet flows throughthe outlet along a flow axis; an overpressure protection device adaptedto stop flow from the inlet to the outlet when pressure in a controlcavity reaches a predetermined level, the overpressure protection devicehaving a sensing tube, the sensing tube having a first end in fluidcommunication with the control cavity and a second end in fluidcommunication with the outlet of the of the regulator valve such thatthe control cavity is in fluid communication with the outlet of the ofthe regulator valve, wherein a first portion of the sensing tube extendsalong a tube axis that is parallel to the flow axis and wherein thefirst portion extends from a first point disposed between the first endand the second end and a second point disposed at the second end, andwherein the sensing tube includes a first segment of the first portionhaving a first diameter and a second segment of the first portion havinga second diameter, wherein the first diameter is larger than the seconddiameter.
 13. The fluid regulating device of claim 12, wherein thesecond segment is adjacent to the second end of the sensing tube. 14.The fluid regulating device of claim 13, wherein a transition segment isdisposed between the first segment and the second segment.
 15. The fluidregulating device of claim 13, wherein a longitudinal length of thefirst segment is at least five times longer than a longitudinal lengthof the second segment.
 16. The fluid regulating device of claim 13,wherein a longitudinal length of the second segment is between two andsix times longer than the diameter of the second segment.
 17. The fluidregulating device of claim 13, wherein the first diameter is between twoand four times larger than the second diameter.
 18. The fluid regulatingdevice of claim 12, wherein the overpressure protection device is anoverpressure monitor.
 19. A fluid regulating device, comprising: aregulator valve having a valve body defining an inlet and an outlet, theregulator valve further including a valve port disposed between theinlet and the outlet; an actuator coupled to the regulator valve andcomprising a valve disc, the valve disc disposed within the regulatorvalve and adapted for displacement between a closed position sealinglyengaging the valve port and an open position disposed away from thevalve port, wherein the valve disc is coupled to a diaphragm, andwherein pressure within a control cavity acts on the diaphragm todisplace the valve disc between the closed position and the openposition, wherein in the open position, fluid flowing from the inlet tothe outlet flows through the outlet along a flow axis; wherein theactuator includes a sensing tube, the sensing tube having a first end influid communication with the control cavity and a second end in fluidcommunication with the outlet of the of the regulator valve such thatthe control cavity is in fluid communication with the outlet of the ofthe regulator valve, wherein a first portion of the sensing tube extendsalong a tube axis that is parallel to the flow axis and wherein thefirst portion extends from a first point disposed between the first endand the second end and a second point disposed at the second end, andwherein one or more apertures are disposed in the sensing tube adjacentto the second end, each of the one or more apertures having a centerlinethat is normal to the tube axis.
 20. The fluid regulating device ofclaim 19, wherein an end wall is disposed adjacent to the second end ofthe sensing tube, the end wall being adapted to prevent fluid flow intoor out of the second end of the sensing tube along the tube axis.